Phase I research adapted primary culture methods to obtain a reliable source of normal human buccal epithelial (NHBE) cells. Tissue culture methods were developed to induce the NHBE cells to differentiate into a three-dimensional organotypic tissue. Characterization showed that the tissue reproduced many of the histological, protein expression, and barrier function properties of native buccal tissue. Initial experiments investigated use of the NHBE tissue for predicting oral irritation and transbuccal drug delivery rates. Finally, an economic evaluation of costs involved in tissue production showed that an NHBE product appears to be commercially feasible. The Phase II work plan will expand upon the results of Phase I to further develop the NHBE and other related, and more complex, oral mucosal models. NHBE culture conditions will be optimized and conditions to produce a gingival phenotype and incorporate lamina propria will be determined. Protocols to predict oral irritation will be determined and use of the tissue for transbuccal drug delivery will be studied in a more comprehensive manner. Finally, studies addressing basic oral biology phenomena, namely anti-microbial peptide regulation and HIV infection, will be performed.